22 



THE OSTEOLOGY OF THE REPTILES 



Ophidia, Amphisbaena, Rhiptoglossa of the Squamata. In the 

 Chelonia (Fig. 30 b) they have been identified with a plate of bone 

 intercalated between the descending plate of the parietal and the 

 basisphenoid of many forms. Their real homologues are yet doubt- 



FiG. 8. Lalidosaurus hamatus Cox>e. Cotylosaur skull: A, right quadrate from 

 below; B, the same from above; C, posterior basicranial bones from above. 



Fig. 9. Labidosaurus hamatus Cope. Cotylosaur skull: from behind. 



ful; by some they have been identified with the alisphenoid of the 

 mammals. 



Supraoccipital {so). (Figs. 9, 21 b, 42 d.) Unpaired, articulating 

 with the parietals and interparietals above, the exoccipitals, par- 

 occipitals, and prootics, and including a part of the semicircular 

 canals formerly believed to be in a separate bone called the epi- 

 otic, but which has never been demonstrated in any air-breathing 



